Atypical rigid form of Huntington's disease: a case with peripheral amyotrophy and congenital defects of a lower limb.

We describe a patient showing an atypical phenotype of Huntington's disease (HD), including prominent generalized dystonia, peripheral amyotrophy of the legs with an inverted champagne bottle configuration and pes equinus. The patient also had congenital defects of the lower left leg. Chorea and psychiatric symptoms were not prominent. Polymerase chain reaction assessment revealed 51 CAG repeats in gene IT 15. Magnetic resonance imaging of the brain demonstrated mild atrophy of the pons and cerebellum, and hyperintensity of the transverse pontine fibers and neostriatum on spin-echo images. Peripheral amyotrophy in this case might have resulted from axonal degeneration related to neuronal damage in the central nervous system, although at the present time we cannot confirm it as a new HD phenotype.